This free VPN works as a Chrome extension, and works with essentially no set-up -- just install, enter your email address, and you're ready to go. As it works, it shows as a small icon of a shield in the address bar. Click it to show your connection status. If you're a Chrome user, this VPN is as simple and trouble-free as it gets. Because it's a Chrome extension, it only works when you're using Chrome.

Hola Unblocker is a Firefox add-on that takes a little bit of work to get installed, and that doesn't work with every site you'll come across. But still, it's free and works with plenty of sites, so is well worth the download. You'll see whether it's active or not by the icon in Firefox's toolbar. Click it to visit more sites, configure it, and more. I had problems with installation. It needed to update itself immediately, and it took four or five attempts to get it to finally install. Because it's a Firefox addon, it only works when you're using Firefox.

This VPN works independently of your browser, so all of your Internet use is protected, not just browser use. It works with Windows machines, Macs and Android devices. There are also no bandwidth caps as there are with some other VPNs. However, with the free version you're limited to three-hour sessions, and you'll see an ad when you first launch it. (The ad then goes away.) You can upgrade to for-pay versions, but there's a good chance you'll stay happy with the free version.

This is a great VPN service, but only if you're technically sophisticated enough to spend a bit of time doing setup. It's a service and a service only, which means that you'll have to use a separate VPN client, and configure the client to work with the VPNBook service. But don't let that scare you away, because once you do that, it works great. There's a useful setup guide that walks you through using the service on Windows, the Mac, Ubuntu, the iPad and Android.

This is probably the most well-known free VPN service, and claims it has had more than 200 million downloads. It's available for Windows machines, Macs, iPhones, iPads, and Android devices. Setup is simple and straightfoward, and so is using it. There's one drawback though -- ads that can feel intrusive. To get rid of them you'll have to subscribe to the for-pay version.